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Q: I have many different types of fish in my water garden. Most were given to me by my friends. I think they are koi but how can I tell the difference between a koi and goldfish? – Troy of Kansas

A: I remember when I first got into water gardening not only did I not know what the heck a water garden was, but pretty much every koi or goldfish I saw in a water garden was a goldfish to me. So how do you tell the difference? Is it by size? shape? Hopefully the following will be able to help you become a basic koi and
goldfish identifier!

Koi and Goldfish are related but not closely. Colors, patterns and body structure are the most distinctive differences between the two fish types.

Colors & Patterns: Did you know that koi varities are named by their color patterns?

Here are some of the most common koi varieties. See the pictures to the left to help identify them:

Kohaku, white koi with red patterns;

Sanke, white koi with red and small black “stepping stone” patterns;

Showa White, red and black patterns fit together;

Bekko Solid color koi with black spots;

Ogon Solid color in with regular or metallic scales just to name a few.

Just like koi there are many varieties of goldfish. Common goldfish found in water gardens are:

Sarassa, red and white patterns;

Shubunkin, “Calico colored” bluish tint with red and black spots;

Commons, Orange, yellow, red, brown, or black

Body Structure: A koi’s body is tapered at each end with pointy noses, barbells/whiskers like a catfish and flat bellies. Koi fins can be well defined (called standard koi by retailers) or long fins (called butterfly koi) shown in the pictures on the left. Scale quantity and placement may vary on a koi as well. Some koi have scales on just a few parts of their body while some may have no true scales at all.

Goldfish tend to be more rounded with a blunt nose and do not have barbells. Goldfish may also have butterfly fins or fan tails. Fan tail fish have divided tail fins that form a triangle shape or fan shape when viewed from above. Scales on a goldfish are more evenly distributed and located all over the fish.

If you would like to know more information about these and other fish types check out the available Reference Books. It’ll make you an expert in no time!

18 Responses

We just moved into our new home and we have a water garden or small pond, when I moved in we had 4 pretty good size fish in it, they are sort of a soft golden orange color. Well I bought 3 fan tail goldfish and 1 white and orange koi. Question is I don’t know if the original 4 fish are koi or goldfish. They are about 6 inches long. Is there an easy way to tell? And can I leave them in the pond in the winter? My pond is about 10’by 5′ across and about 3′ deep at the deepest point.

My koi are slowly disappearing in my creek. I know that the raccoon and neighbor cats probably eat them, but do you know if skunk eat them also? Also, if I want to put the koi in an aquarium, what kind of water should I use? I had city water. Thanks!

Hi Rose – Skunks typically will not enter water to eat. They prefer to dig in the ground for worms and grubs.

Are you planning on overwintering the koi in the aquarium? I would recommend using your pond water to fill the aquarium, that will cause the least amount of stress to your fish. If you need to do water changes, you can use your city water but don’t forget to add Water Conditioner to remove chlorine and other metals.

I have a question. I recently received a fish from a friend. Her mother heard she was starting an aquarium, so she went out to Petsmart and bought a goldfish, a koi, and a pictus catfish. I know….I’d love to slap whoever sold her that combination. My friend is doing a tropicals tank, so she kept the catfish, and wanted to give me the goldfish and/or koi. Before I could get over there, according to my friend the goldfish died. i went ahead and took the koi (since otherwise her husband was going to flush it) and put it in my goldfish tank (a 29g with an 8 inch Shubunkin mix, 4in red/white Ryunkin, and 4-5in Black Moor). I know…crowded at the moment. I added an extra filter for the time being.
Here’s my question. I keep looking at this fish wondering if it is indeed a koi. It is about 3-4in, colored exactly like my Shubunkin (though without the long, long flowy fins), and does NOT have barbels…at least not that I can see. I looked on Petsmart.com, and sure enough their pictures of koi include one with and one without barbels. So last time I was out that way I went in and looked. Sure enough, there was an entire tank or two labeled as koi that did not have visible barbels.
I will gladly send pictures. I guess it’s not that big of a deal…regardless the fish cannot stay in that tank indefinately. I just admit I’m a bit confused….plus I think barbels are cute😉 *L*

Koi will have barbells. They may not be visible in the early stages of a Koi’s life, but they are there. Usually a Koi’s barbells develop and become visible within the first year. So it could be possible that you have a very young Koi.

Fun Facts About Koi:
Koi actually have small teeth in the very back of there throat to break up any crustaceans they may ingest. But don’t worry! Koi cannot bite you and can be trained to feed from you’re hands!
Koi can eat up to 2% of their body weight a day!
Koi varieties depend on their coloring.

First of all, thank you for taking the time to give all of the info.
Just like the other person that wrote in,( a friend of my husbands,in my case), gave me his ” koi.”
He apparently had pond for a year or two then sold his house. He kept the fish for a while thinking to build one in his new yard. He decided not to and gave me his fish. At this point though I am seriously wondering if they are really koi as they are the same size,if not smaller than my pond gold fish. Like the previous writer I am also having an impossible time seeing any whiskers. How pronounced should they be ?
Rhonda

This will really depend on the size of the fish…small koi will be difficult to see the wiskers and on larger koi maybe a few centimeters. The better determination is the body of the fish itself. When looked at the from the side Koi have a much flatter belly and goldfish will be skinnier from the top view but have a much more rounded belly appearance from the side. Color patterns are also an indication as most goldfish are gold and black or speckled such as a shubunkin while koi generally have larger patches or 1 to 2 different colors. If you have any clear pictures of them you can e-mail them to pondhelp@thepondguy.com and we may be able to tell if they are koi or goldfish.

Hi Ralph – Yes, koi can grow that large. Like you and me, it’s largely dependent on their genes and the type of food they are eating. A high quality koi food, like Growth & Color, will help to provide the proper nutrients for koi.

Thanks for the post! I have a mixture of comets and koi and I am always trying to tell which are which. I do look for barbels but they are not always easy to see. I recently lost several fish that I thought were comets to a pH crash. It was only under close examination after I removed the dead ones that I was able to see small barbels.

Have you ever noticed that pictures of koi always seem to be taken from overhead and pictures of others (like in your post) are taken from the side? This makes it hard to really compare them, especially since most of us who have ponds never get to see our fish from the side. Do you have any pictures that show direct comparrison from a top view of the different kinds of fish?

Yes I have noticed that =). My apologizes. Most of the reason is because the goldfish are taken in an aquarium where you can see them from the side while the koi, a majority not all, are taken top down since they are in a blue tank in a koi show. Once we get our goldfish in our retail store, I will try and get some better pictures uploaded.

Sid, Koi and Goldfish are pretty hardy and can survive freezing temperatures. If your water temperatures are staying around 50-60 degrees, they will be just fine. If you notice that your fish are starting to slow down in the cooler water temperatures, you may want to switch to a Wheatgerm based fish food like Pond Logic® Spring and Fall Fish Food so that they can digest easier in the cooler temperatures.

I have Koi and goldfish in my 3,000 gallon pond. They are about 4 inches long. They have been there for 1 year. I added 3 new 2 inch Koi to my pond 5 days ago and they have not come up to eat and I have not seen them. What do you think happened? I have not found them floating dead or in the skimmer.

What happens some times when adding new koi is they can become a little skittish and hide as you approach your water garden. This is because it is a new environment that they are not used to. This post on Acclimating Your Koi & Other Fish should be helpful to you. Thanks for the Question!